The rooms in which lavatories are housed can be rendered unpleasantly odorous after use of the lavatory, and partly for this reason these rooms are sometimes equipped with extractor fans to communicate the room atmosphere with the atmosphere outside the building. It has also been proposed to provide the lavatory with an air extraction means. In these known proposals, the lavatory seat has been provided with an internal air channel leading from air inlets at the inner periphery of the seat to an air extraction outlet at the outer periphery of the seat, the air extraction outlet communicating with an air outlet tube or pipe through which air is drawn by a fixedly mounted fan into a stench pipe or the atmosphere outside the building. Because the seat is hinged to the lavatory pan, various difficulties arise, including that of providing communication between the internal air channel of the hinged seat and the fixed fan (or associated fixed passageway in which the fan is mounted). Commonly, a flexible hose is employed to connect between the air extraction outlet of the hinged seat and the fixed fan structure. This flexible hose tends to be conspicuous, and it can affect the free hinging of the seat.